cgtimer_sub is now the same since cgtimer_t should be the same on all platforms.
Move two more timer functions out of define macros to enable them to be used by future osx code.
Provide an osx fix for cgtimers and a fallback to timevals for all other platforms !linux !win32 !osx.
Merge branch 'master' of github.com:ckolivas/cgminer